Field of the Invention
The present invention relates generally to the field of devices for removing foreign material from a body of liquid.
Description of the Prior Art
Many different types of reservoirs including tanks for holding a variety of liquids accumulate foreign material at the bottom of the reservoir or tank. Various types of devices have been provided in an attempt to remove the foreign material, typically through the use of air lift pumps requiring expenditure of large amounts of energy. The expense associated with the removal process adds significantly to the overall cross of maintaining the reservoir and tank. Particularly, in the field of raising shrimp or fish, the foreign material in the water can result in the development of a virus negatively impacting the shrimp. It is possible to place chemicals in the water in an attempt to control the virus; however, certain customers object to the use of chemicals detracting from such an approach. Other approaches include genetically engineering the shrimp to avoid the negative impact of the virus. The ultimate solution is to provide clean water for the raising of the shrimp or fish. I have therefore tried many approaches in providing the cleanest water possible to avoid the above problems.
One possible approach is to provide a cone shaped container in which the water is swirled to a bottom drain whereat the waste material is removed. Such an approach again takes considerable energy. Large outside reservoirs provide a very difficult hurdle in such an approach due to the quantity of the water. An object of this invention is therefore to provide clean water in the reservoir or tank in an efficient and low cost manner.
In the U.S. Pat. No. 4,181,614 assigned to The British Petroleum Company Limited, there is disclosed a horizontally extending pipe having a sloping inverted channel connected at its highest point to a riser pipe. Gas in introduced into the sloping inverted channel to direct the foreign material within the liquid to the riser pipe.
Another approach is disclosed in the U.S. Pat. Nos. 5,772,885 and 6,234,323 issued to Sarrouh which use a horizontally extending conduit moved horizontally on a track across the tank bottom. Both the '885 and '323 patents are directed to removing sludge from a wastewater treatment facility.
Another approach is disclosed in the U.S. Pat. No. 7,105,096 issued to Meurer which employs a horizontally extending pipe connected to a vacuum pump causing low pressure to be applied to the pipe for the removal of sludge from the floor of a basin.
The U.S. Pat. No. 4,600,338 issued to Van Bruwaene et al. discloses a device for removing high density foreign material from the bottom of a body of water by means of a horizontally extending intake duct connected to a riser pipe having an airlift pump thereon. U.S. Pat. No. 5,161,914 issued to Rahn et al. discloses a horizontal trench having a perforated casing attached to a vacuum pump by means of a vertical riser, U.S. Pat. No. 1,703,041 issued to Imhoff discloses a device for supplying compressed air at the bottom of a tank to drive oil particles within sewage to the top level of the tank whereat they are removed. U.S. Pat. No. 8,372,274 issued to Early et al. discloses a wastewater treatment system utilizing pumps and filters for decontaminating the wastewater.
In order to remove the foreign material including sludge from the body of liquid while using minimum energy, I have devised an inverted u-shaped conduit that extends along the bottom of the reservoir or tank that, in turn, is connected to a vertically extending outlet pipe. The conduit includes a restricted channel into which gas is directed to pull the foreign material through the inlets of the horizontally extending conduit and then through the channel to the upper most surface of the cavity of the horizontally extending conduit. The uppermost surface slopes gently upward allowing the gas bubbles to move the foreign material and liquid toward the outlet pipe. The upward slope of the innermost surface of the conduit enables the gas bubbles and liquid flow to move under the force of the gas pressure towards the outlet pipe. The channel is formed by an insert located in the cavity having upwardly facing surfaces opposed to the downwardly facing surfaces of the conduit.
A circular or part circular tank is used in certain instances instead of using an elongated reservoir or tank for holding the shrimp or other animals. I have therefore devised a cone shaped device for fitting inside the circular tank for lifting the foreign material and liquid from the bottom of the tank toward the outlet pipe. A major hurdle encountered in designing the device was to minimize the energy required to lift the material and liquid. By using a flow channel which increases in size as the material moves from the bottom of the tank coupled with an arrangement of injecting air into the channel, the amount of energy is minimized. Disclosed herein is such a design. Further, I. have discovered that by using the flow channel which increases in size as the material moves from the bottom of the tank coupled with the arrangement of air injection allows a great increase in the volume of liquid that is moved with a small amount of energy. Thus, such a cone shaped device is not restricted to use with only a circular tank or reservoir but also may be used with an oblong or elongated tank. It is further possible to place multiple cone shaped devices along the length or width, of the circular, oblong or elongated tank depending on the volume of water to be moved.